Fig. 3. Sem images of the porous dual-core-type granules after sintering. (A–A5) P8-Sr4@Zn3; (B–B5) P8-Sr4@Tcp; (C–C5) P8-Sr4@Har. The yellow and blue circles are the dual-core component (P8-Sr4) after sintering. The red arrows indicate the pore structures left by PMMA.